The Hardrock "porphyry" of the Little Long Lac gold mining district of northwestern Ontario is a rock of considerable economic interest in that area, as some of the ore deposits worked in two of the leading mines--the Hardrock and the MacLeod Cockshutt--are definitely connected with it. It is of puzzling and anomalous character and diverse opinions have been held at different times as to its nature and origin. The writer, however, as the result of recent studies, has come to the conclusion that it is an arkose and part of the general assemblage of sedimentary rocks of the district.

First Page Preview

First page PDF preview
You do not currently have access to this article.